Shuuichi Honda is a 30-year-old Japanese businessman with dark brown hair and brown eyes, standing 1.76 meters tall and weighing 65 kilograms. He serves as the chief of the sales department at a trading company.

He married Nanami, a former subordinate, following a year-long courtship that began during their professional relationship. The narrative picks up around their third wedding anniversary, depicting a life that appears happy and supportive.

Shuuichi is a late bloomer, relatively inexperienced with women, which fuels a persistent undercurrent of insecurity and unease. He frequently questions his own worth and his ability to satisfy his wife emotionally and physically. This contrasts with his nearly boundless trust in her, leaving him largely unaware of her external struggles.

He is more of an indoor person, often needing encouragement from his wife to go out. He has a severe allergy to cats, and his favorite food is gratin, a dish that is his wife's specialty.

His development involves confronting serious threats to his marriage. In some outcomes, he discovers his wife is being blackmailed and fights to save her, successfully rescuing her from a blackmailer named Yoyogi and reaffirming their love. In another path, their marriage remains untouched by outside forces; they celebrate their third anniversary happily, and Nanami becomes pregnant.